<template>
	<view>
		<view class="scroll-view-container">
			<!-- 左侧的滑动区域 -->
			<scroll-view class="left-scroll-view" scroll-y="true" :style="{height: wh+ 'px'}">
				<block v-for="(item,i) in cateList" :key="i">
					<view :class="['left-scroll-view-item', i===active ? 'active':'']" @click="activeChanged(i)">{{item.cat_name}}</view>
				</block>
			</scroll-view>
			<!-- 右侧的滑动区域 -->
			<scroll-view scroll-y="true" :style="{height: wh+ 'px'}" :scroll-top="scrollTop">
				<view class="cate-lv2" v-for="(item2,i) in cateLevel2" :key="i2">
					<!-- 二级分类的标题 -->
					<view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
					<!-- 二级分类下的三级列表 -->
					<view class="cate-lv3-list">
						<!-- 三级分类的item项 -->
						<view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
							<!-- 三级分类的图片 -->
							<image :src="item3.cat_icon"></image>
							<!-- 三级分类的文本 -->
							<text>{{item3.cat_name}}</text>
						</view>
					</view>
				</view>
			</scroll-view>
		</view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				//当前设备可用的高度
				wh:0,
				cateList:[],
				active:0,
				//二级分类的列表
				cateLevel2:[],
				scrollTop:0
			};
		},
		onLoad() {
			const sysInfo=  uni.getSystemInfoSync()
			console.log(sysInfo)
			this.wh=sysInfo.windowHeight
			
			this.getCateList()
		},
		
		methods:{
			//获取分类列表的数据
			async getCateList(){
				const {data:res} = await uni.$http.get('/api/public/v1/categories')
				if(res.meta.status !== 200) return uni.$showMsg()
				this.cateList=res.message
				
				//为二级分类赋值
				this.cateLevel2= res.message[0].children
				},
				activeChanged(i){
					this.active = i
					
					//重新为二级分类赋值
					this.cateLevel2=this.cateList[i].children
					
					this.scrollTop=this.scrollTop===0?1:0
				},
				//跳转到商品列表页面
				gotoGoodsList(item3) {
				  uni.navigateTo({
				    url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
				  })
				}
			}
	}
</script>

<style lang="scss">

.scroll-view-container{
	display: flex;
	
	
	.left-scroll-view{
		width: 120px;
		
		.left-scroll-view-item{
			background-color: #f7f7f7;
			line-height: 60px;
			text-align: center;
			font-size: 12px;
			
			&.active{
				background-color: #ffffff;
				position: relative;
				
				&::before{
					content: '';
					display: block;
					width: 3px;
					height: 30px;
					background-color: #C00000;
					position: absolute;
					top: 50%;
					left: 0%;
					transform: translateY(-50%);
				}
			}
		}
	}
}

.cate-lv2-title{
	font-size: 12px;
	font-weight: bold;
	text-align: center;
	padding: 15px 0;
}

.cate-lv3-list{
	display: flex;
	flex-wrap: wrap;
	
	.cate-lv3-item{
		width: 33.33%;
		display: flex;
		flex-direction: column;
		justify-content: center;
		align-items: center;
		margin-bottom: 10px;
		
		
		
		image{
			height: 60px;
			width: 60px;
		}
		text{
			font-size: 12px;
		}
	}
}

</style>
